This category includes casualties caused by suicide bombers detonating in populated areas and targeted killings, but excludes those caused by ground fighting, airstrikes and explosions aimed principally at military targets, like some roadside bombs.
Over all, the 84-page report notes, the number of civilian casualties declined 9 percent compared with the record numbers seen in 2016, driven primarily by a drop in casualties caused by ground clashes. It was the first annual decline in overall civilian casualties since 2012.
The report also says that despite a stepped-up pace of aerial bombardments aimed at the Taliban and Islamic State militants under President Trump’s new strategy for the war, civilian casualties from airstrikes rose only 7 percent. The United Nations credited better targeting in the American-led air campaign, compared with previous years.
The Taliban’s response to the airstrikes, however, has been ferocious, indicating that what Afghan officials openly call a Pakistani-backed insurgent group is hardly a spent force.
The report put a spotlight on “complex attacks,” a type of suicide assault that is becoming more deadly, United Nations officials say. These involve two or more commandos with suicide vests seizing a building or taking hostages, fighting for hours and detonating their explosives only when security forces close in.
Such attacks have recently become a hallmark of the war. The ensuing mayhem sends a clear message: that the Taliban can strike at will, even in ostensibly safe cities like Kabul, where the “ring of steel” security cordon around the capital has been looking more like a colander.
Deaths from complex attacks and other suicide bombings rose to 605 last year from 398 in 2016, according to the report, with the highest number of civilian casualties in Kabul.
One of the deadliest single episodes of the war for civilians took place last May, when a gigantic truck bomb estimated to contain two metric tons of high explosives went off on a Kabul street during rush hour, killing 92 and wounding 491 people.
The Taliban have also stepped up assassinations in the countryside, targeting doctors delivering polio vaccinations, workers on demining teams and religious leaders who preach against the group, among others, the United Nations said. The report blamed the Islamic State’s Afghan branch for 1,000 civilian casualties — 399 killed and 601 wounded.
In a statement that the United Nations included with the report, the Taliban denied targeting civilians and blamed the United States and its allies for waging war in Afghanistan in the first place. “For the past 17 years, hundreds of thousands of innocent Afghans were killed after the influx of foreigners, and they are still being killed,” it said.
Atiqullah Amarkhel, a retired general and military analyst based in Kabul, said the report illustrated the failure of peace talks, as both the government and the Taliban were striving now for victory rather than a negotiated settlement. “The war has intensified. More airstrikes mean more suicide attacks” in retribution, he said.
Airstrikes — which are carried out only by the United States-led international forces, in an operation now called Resolute Support, and the Afghan Air Force, not by the Taliban and their allies — killed 295 civilian bystanders and wounded 336 more, the report said. That was the highest toll since the United Nations started counting in 2009, and possibly for the entire war.
But the casualty rate did not rise as fast as the tempo of air operations, a cornerstone of Mr. Trump’s new strategy. The report said that reflected better targeting. “While emphasizing that no civilian casualties are acceptable, the reduced harm ratio suggests improvements,” it said.
Still, the air war continued to take a toll on innocents.
The report cited an airstrike on Aug. 30 in the eastern province of Logar, apparently targeting a Taliban fighter who was lurking beside a house with a rocket-propelled grenade launcher. The strike killed 10 children and three women in the house, according to witnesses who spoke to United Nations researchers.
The report quoted a family elder, who was not identified, as saying, “This was too much for just one Taliban.”